Method and apparatus of seek end polarity detection for optical disk drive

Abstract

The present invention discloses a method and apparatus of seek end polarity detection for an optical disk drive. The method comprises the steps of providing a horizontal level between the peak and the trough of the tracking error signal when the tracking error signal is used to determine the polarity of the tracking error; and determining the tracking error polarity by examining whether or not the adjacent waveform level is smaller or larger than the horizontal level after the tracking error signal passes through the horizontal level.

1 . A method of seek end polarity detection for an optical disk drive, comprising the step of: 
 providing a horizontal level, arranged between the peak and trough of a tracking error signal, while making an evaluation to determine the polarity of the tracking error signal according to the tracking error signal; and    determining the polarity of the tracking error signal according to an adjacent waveform level following the horizontal level by comparing the waveform level to the horizontal level.    
   
   
       2 . The method of  claim 1 , wherein said horizontal level further comprises a positive horizontal level and a negative horizontal level.  
   
   
       3 . The method of  claim 2  further comprising: 
 determining the polarity of the tracking error signal as positive if the seek action of the optical disk drive being performed from inner tracks to outer tracks and the adjacent waveform level is smaller than the negative horizontal level after the tracking error signal passes through the negative horizontal level.    
   
   
       4 . The method of  claim 3  further comprising: 
 determining the polarity of the tracking error signal as positive if the seek action of the optical disk drive being performed from inner tracks to outer tracks and the adjacent waveform level is larger than the positive horizontal level after the tracking error signal passes through the positive horizontal level.    
   
   
       5 . The method of  claim 4  further comprising: 
 determining the polarity of the tracking error signal as positive if the seek action of the optical disk drive being performed from outer tracks to inner tracks and the adjacent waveform level is larger than the positive horizontal level after the tracking error signal passes through the positive horizontal level.    
   
   
       6 . The method of  claim 5  further comprising: 
 determining the polarity of the tracking error signal as positive if the seek action of the optical disk drive being performed from outer tracks to inner tracks and the adjacent waveform level is smaller than the negative horizontal level after the tracking error signal passes through the negative horizontal level.    
   
   
       7 . The method of  claim 2  further comprising: 
 determining the polarity of the tracking error signal as positive if the adjacent waveform level is larger than the positive horizontal level after the tracking error signal passes through the positive horizontal level; and    determining the polarity of the tracking error signal as positive if the adjacent waveform level is smaller than the negative horizontal level after the tracking error signal passes through the negative horizontal level.    
   
   
       8 . The method of  claim 7  further comprising: 
 determining the polarity of the tracking error signal as positive if the adjacent peak level is larger than the positive horizontal level after the tracking error signal passes through the positive horizontal level; and    determining the polarity of the tracking error signal as positive if the adjacent trough level is smaller than the negative horizontal level after the tracking error signal passes through the negative horizontal level.    
   
   
       9 . The method of  claim 1  further comprising: 
 providing the horizontal level to a waveform of the tracking error signal on a track in front of a target track.    
   
   
       10 . An apparatus of seek end polarity detection for an optical disk drive, comprising: 
 a velocity profile for generating a speed curve signal;    a subtractor, for receiving said speed curve signal and a zero cross speed signal to output a speed error signal;    a control unit, further comprising:    a track controller for receiving a tracking error signal to output a control signal;    a seek end polarity detector for receiving and detecting a polarity of said tracking error signal to output a polarity determination signal of said tracking error polarity;    a seek controller, for receiving said tracking control signal and said polarity determination signal to output a control signal;    a first electronic switch, for switching a signal outputted from said track controller and said seek controller;    an optical pickup head, for reading and writing data on a disk in said optical disk drive;    a driver, for receiving a signal outputted from said electronic switch to control the movement of said optical pickup head;    a pre-amplifier, for receiving a signal outputted from said optical pickup head to output said tracking error signal and a tracking error zero cross signal; and    a speed calculator, for receiving said tracking error zero cross signal to output a zero cross speed signal.    
   
   
       11 . The apparatus of  claim 10  further comprising: 
 a seek direction/target track selector, for receiving a signal for controlling said optical disk drive to control said optical pickup head to jump from outer tracks to inner tracks to output a control signal;    a positive level detector, for providing a positive horizontal level for said tracking error signal and detecting the position of the highest point after said tracking error signal passes through said positive horizontal level;    a negative level detector, for providing a negative horizontal level for said tracking error signal and detecting the position of the lowest point after said tracking error signal passes through said negative horizontal level; and    a second electronic switch, for receiving said tracking error signal and switching the output of said tracking error signal selectively to said positive level detector and said negative level detector according to said control signal.